AU9721801A - Delivery and ejection device for a machine which processes flat elements - Google Patents

Abstract

The reception and ejection device for flat elements (2) in a packaging production machine (10). The machine continuously delivers several rows of elements placed into parallel layers (22) successively onto three conveyor belts (13,23,33). The layers are cylindrically unloaded into a stacker (40) by means of a layer driving and interrupting mechanism (60). The device allows the separate ejection of a layer to a waste conveyor collecting the flat elements detected as being defective. The mechanism comprises upper (61) and lower (62) trolleys which can move at the same speed in opposite directions along an axis parallel to the row of layers.

Description

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AUSTRALIA

Patents Act 1990 Bobst S A COMPLETE SPECIFICATION STANDARD PATENT Invention Title: Delivery and ejection device for a machine which processes flat elements The following statement is a full description of this invention including the best method of performing it known to us:- DELIVERY AND EJECTION DEVICE FOR A MACHINE WHICH PROCESSES FLAT ELEMENTS The present invention relates to a delivery and ejection device for a machine which processes flat elements. In particular the machine may be a packaging production machine for the manufacture of cardboard boxes from a web or sheet material.

Such machines generally include several stations arranged one after 10 another, typically allowing printing of the used material, cutting of it according to a reference shape by means of a rotary tool for example, then rejection, on one hand, of the inconvenient waste resulting from cutting and, on the other hand, of all unsuitable blanks before collecting the other boxes blanks in a delivery station.

The subject of the invention is useful the final operation. The processed sheets or cardboard web can generally include in their width several identical boxes blanks or cuttings, each one representing the shape and the developed surface of a manufactured package. The quantity of blanks which can be thus laid out side by side depends of course on the width of the worked support, but also on the maximum suitable format for the machine and on the size of the boxes blanks.

Once achieved, these boxes blanks are laid out, in the delivery station, in 2 parallel lines of streams on conveyor belts. This shingling, that is to say that blanks overlap or partially overlie one another, is due to the fact that the conveyor belts are moving more slowly than the feeding sheets or cardboard web.

There are thus as many streams rows as much blanks in the width of the worked support. The streams are then regularly collected by a stacker which forms piles which are finally delivered onto a carriage or, by another belt conveyor, towards a storage station for example.

EP 316'477 and EP 317330 describe similar devices which allow the quick stacking of the downwards part of a single stream of flat elements so as to 10 be piled up. These shingling and sheets stacking devices operate continuously without the need to stop the shingling operation during the pile removal. To do so, these devices include two overlapping conveyors with parallel belts so that the second conveyor is settled onto the longitudinal axis of the first one and can slightly go up and down through the latter. Initially, the two conveyors are moved 15 at the same speed. When the leading part of the stream includes enough sheets to S* make a pile of several of them, the second conveyor raises itself slightly above the plane of the first one and carries, at high speed, the corresponding stream part to deliver it onto a plate against a stop along which the aforementioned pile will take place. Initially settled in high position, this plate descends progressively according to the sheets stacking so that the falling height of the sheets is constant in order to ensure a good stacking. The sheets pile must then be lowered until an 3 output level where it will be removed from the plate before this last one can raise again to be able to deliver the next pile of sheets. Meanwhile, the second conveyor has been lowered and replaced in its initial position under the new leading edge of the stream which was continuously travelling thanks to the regular drive of the first conveyor. A new operating time can thus start again. The operations intended for the pile formation, its removal from the plate and the raising again of this latter in its initial position must of course succeed quickly I enough to avoid, in all cases, the new edge of the stream to be almost engaged and to fall too early from the first conveyor.

10 Another device for forming form piles of sheets starting from shingled elements is described in CH 633'761. It includes several conveyors, each one comprising a rolling conveyor belt arranged into the whole width of the machine.

On this width, several parallel shingle stream of blanks can fit. This device can also receive and pile up boxes blanks without decreasing the machine production 15 rate which is secured to it by virtue of a braking device which stops the run of the streams. This stop temporarily increases the thickness of the streams. The last conveyor belt is settled so that it can turn around its control shaft, which allows, if necessary, to have the streams path deviated onto another waste removal conveyor belt. This path deviation occurs if imperfections in the printing or in the manufacturing of the boxes blanks would have been scanned by control devices located upstream. The piles of each stream are then simultaneously arranged Onto 4 a carriage movable in a vertical direction, then moved by a push rod onto a transverse conveyor which removes them.

One disadvantage of this device relates to the stripping of the imperfectly printed blanks which must be driven out of the normal path. Depending on the nature and the origin of the defects, one specifies that the latter can of course modify only one row of blanks, when ignoring the other rows simultaneously produced. However, in this device, the report of a defect on one part of an unspecified stream means not only the stripping of this latter but also the stripping of all other adjacent stream parts which are simultaneously on the same o• 10 conveyor belt. It generates a waste, of course undesirable, which can become .o proportionally significant, especially when carrying out small production runs.

GB 2'074'990 describes another device allowing the delivery of certain quantity of sheets starting from a stream travelling continuously through a delivery station. As it is the case for almost all delivery devices, it is necessary to 0 enter a stop in the continuous flood of the sheets stream in order to handle with a minimum necessary time for the stripping of the pile and for the replacement of the means used to deliver the next pile. To this end, the device as described in GB 2'074'990 is made of two end to end telescopic conveyors. Each conveyor is made of an endless belt set into rotation around a plurality of tracks or rollers.

The rotation speeds of these belts are interdependent the one from the others. The front end of the first conveyor and the back end of the second conveyor, which faces it, are assembled onto a same carriage which can move longitudinally forwards to backwards into the moving direction of the stream. When the stacking is almost achieved, one must deal with a stop in the stream moved by these two conveyors. To do so, the aforementioned carriage moves in the downstream direction and the speed of the second conveyor is increased in order to release quickly the second conveyor from its loading and to generate thus a sufficient time allowing the stripping of the pile. Once the delivery support is ready to receive a new pile, the speed of the second conveyor is reduced and the carriage returns upstream to its initial position.

10 Although it is running with satisfaction, this device suffers from a first defect related to the carriage size which is necessary dependent from the length of its run. Indeed, as it is performed for this invention, one can note that the length of the carriage must be in all cases more important than the maximum length of its movement. However, if one wants to reach higher production rates, it is also necessary to increase the run of the movable carriage, which means in fact to have to perform with a carriage which is longer and the more imposing. Another defect of this device results from the repeated movement of the carriage. To be able to perform the longest possible stop of the stream, it is necessary to return the carriage as quickly as possible. However, being at evidence of a relatively large size, this carriage represents also a significant moving entity which, on one hand, requires a powerful moving mechanism and then a braking mechanism and which, on the other hand, must be controlled by a massive surrounding support structure. Moreover, the inertia of this carriage continuously generates large shocks in the machine frame. The whole range of these undesirable factors and mechanical constraints arise from dealing with a heavy, cumbersome and expensive equipment.

All these devices also show another disadvantage which relates to the stacking. This operation needs a support, movable in the vertical plane, which successively goes from a high initial position, when it is empty and ready to S" receive a new pile, to a low output position allowing the side unloading of the 10 pile. Although this way of operating is reliable and works well, it needs however a whole range of operations which can only be carried out sequentially. As it seems at first to be impossible to reduce much more the useful time to carry out each separate operation, it is also impossible to reduce the total time needed to *0 discharge the pile and to raise up again the support in its initial position, considering that the support can be raised up again only once the pile is discharged.

Another disadvantage is due to the fact that these devices, either do simply not allow to rejection of sheets of insufficient quality, or excessively extend this operation to a whole range of the production by eliminating all the sheets within the width of the machine. To carry out this stripping operation, another more accurate solution consists in rejecting the sheets of bad quality one by one, in a 7 quality controlling and stripping device before these ones are shingled. However, located into the production line upstream from the delivery station, such a device is, on one hand, not intended for the stripping of already shingled sheets and, on the other hand, means an additional module for the production line, which is completely dissociated and different from the object of the present invention.

The present invention has as an object to deal with the above mentioned disadvantages by providing a delivery and ejection device for flat elements which is fast, economic, universal and easy to deal with. With the wording economic, Sone will understand that this device has to be manufactured at low cost, but must 10 also avoid any kind of waste while quickly sorting the parts which are comprised within the quality standards from those with defects having to be rejected from the production line. With the wording universal, one intends to provide a device which can suit at the same time with a whole range of goods of different formats and ensure an easy way to deal with so as to work with each one of these products while reducing as much as possible the settling operations of the delivery device between two series of different operations. Thus, the object of this invention must be easily adaptable so as to deliver as well wide box blanks, such as for example 1 or 2 blanks in the whole width of the machine, as smaller boxes blanks numerously divided (for example 10) into the width of the machine.

This device must also be able to reject quickly and with less waste all boxes blanks which are not included within the required quality standards. One will note 8 that to effectively suit this last speed condition, it is at this point already impossible to think of carrying out such a sorting sheet after sheet before the latter are shingled.

To this end, the present invention provides delivery and ejection device in conformity with what is stated in claim 1.

The invention will be more readily understood from one embodiment without limiting force and illustrated in the accompanying figures wherein fig. I represents a schematic front view of the device according to the invention in a first situation, 10 fig. 2 represents a simplified schematic plan view of the device as shown on fig. I, fig. 3 represents a schematic front view of the device according to the invention in a second situation, fig. 4 represents a schematic sectional view, according to the line IV-IV of fig. 1 of a part of the driving mechanism of the device according to the S invention, fig. 5 represents the downstream part of the device of the invention in a different situation than the one illustrated on fig. 1 and 3, fig.6 represents a partial sectional profile view, according to the' line VI- VI of fig. 7, of an output ramp of piles of sheets, fig. 7 represents a detailed partial sectional view of the output track illustrated on fig. 6.

In order to define some wording usually used in the following description of the orientation or the localization of some parts of embodiments, one will note that the words 'longitudinal" and "transverse" always deal with the main run axis of flat elements intlo the machine, and that the words "upstream" and "downstream" respectively mean the side which is in the vicinity of the machine input and the one which is in the vicinity of the machine output.

Fig. I represents a schematic front view of a device 20 for delivery and ejection of flat elements, such as cardboard sheets 2, in a first situation where a :400010 stream 22 of sheets 2 are moved upstream to downstream in the longitudinal direction of the machine according to the direction shown by arrow 1. For practical reasons issued from use tests, a very tight stream of sheets, such-as stream 22 in device 20, cannot be directly assembled starting from sheets 2 'fee travelling one after another at very high speed. Thus, the delivery device 20 needs to be preceded by a unit 10 conveying a first stream 12 sheets 2. more spaced than those of stream 22, between a conveying belt 13 moved at reduced speed by OVOO:a driving roller 14 and a range of pressure rollers 15 pressing and slowing down sheets 2 against the conveying belt 13 when they arrive and shingle at high speed into the unit The stream 22 is achieved on a second conveying belt 23 comprised in the delivery and ejection device 20 of sheets 2. This conveyor belt 23 fills, as well as all conveying belts of this device, the whole width of the machine. It is actuated by a driving roller 24 which makes it turn, at a lower speed than that of the conveying belt 13, around a plurality of rollers or idling rollers 25, 26, 27, 28 and 29.

Driven in the direction shown by arrow 1, the stream 22 travels then on a third conveyor belt 33 which is rotated by another driving roller 34 which is, as well as the other driving means, completely interdependent. The conveyor belt 33 turns, into the direction of arrow 1, around other rollers or idling rollers 35, 36, 37, 38 and 39.

10 After the conveyor belt 33 a stacker 40 collects the stream sheets 2 on a plurality of tracks 41, adjustable in the width of the machine, so as to form a pile 42 which, as illustrated on fig. 1, is finally ejected out of device 20 and of stacker 40 in the direction of arrow 4 by one or more belts 43 provided on each track 41. The stacking of sheets 2 is carried out on the tracks 41 by displacement 15 of the downstream end of the conveyor belt 33 in the vertical plane so that the height of the falling down of sheets 2 onto the top of the pile is constant. To this end, the roller 36 is interdependent from a lifting platform 50 made up of a frame 51 vertically movable as illustrated by the double arrow 3. This frame 51 is secured, on each side, to a chain 52 extending around sprockets 53. The drive of the chain is achieved by means of an engine 54 coupled to one of the sprockets 53.

11 Fig. 2 shows a simplified schematic plan view of the device as shown on fig. 1. In fig. 2, four illustrated parallel lines 9 of sheets stream are shown which progress into the direction of arrow 1 of the first conveyor belt 13 towards the other conveyor belts 23 and 33 before stacking distinctly on belts 43 of tracks 41.

To improve the understanding of this figure and to help illustration, only one line 9 of shingled sheets is shown in full. Only the shapes of the three other lines are to be seen. Moreover, the idling rollers of the ends of the conveyor belts are removed and shown here only by their axis in dotted lines. In the following description and in order to simplify the explanations, one will Uu~ally deal with 10 the course and the description of the sequences of only one line 9 of shingled sheets. Hence, it is of course necessary to keep in mind that the same operations are carried out simultaneously and in synchronism on all the sheet lines travelling towards the conveyor belt 33, whatever the number of these lines is.

9 Fig. 3 shows, in a similar way to fig. 1, a device according to the invention in a second different way from the one illustrated on fig. 1. The drawings of two figs. I and 3 allow a better understanding of the operation of a device in accordance with the invention which will be described now, One of the aims stated for delivery devices of this type resides in being able to have piles of a certain number of sheets without having to stop the continuous production of the sheets delivered upstream by the printing machine. In this presentation, the continuous production of sheets 2 is illustrated by the unit 10 which creates 12 continuously the movable stream 12. On the conveying belt 23, this latter is simply condensed into a stream 22 by means of lowering the conveying speed. As this production flood is continuous, it is necessary to enter a stop in this stream 22 which allows the saving of useful time, particularly to form the corresponding pile of sheets 42, to reject this pile out of the stacker 40 and simultaneously replace the stacker parts in a new initial position ready for the delivery of the next pile. To do so, a device in accordance with the present invention is equipped with a driving mechanism 60 and a stream stopping mechanism which allows variation of useful lengths of the conveying belts 23 and 33. This mechanism is 10 located, in device 20, in the middle, between the conveying belts 23 and 33. It comprises two carriages, an upper one 61 and a lower one 62, which can move horizontally from upstream towards downstream and conversely. The moving of these two carriages is completely interdependent one with another so that the speed of one of the carriage is always similar to the speed of the one and their 15 direction of movement is always in opposition. Such a device is achieved by means of the engaging of toothed racks, secured to said carriages, onto a pair of toothed wheels turning alternatively in one direction then in another, as described in more detail below.

Fig. 4, illustrates a section on line IV-IV of fig. 1, allows a better understanding of functioning and the layout of the driving device 60 located between the two main elements which constitute the frame 70 of device 20. To 13 allow understanding of this fig., one will note that the conveying belts and the sheets streams are not represented. In the upper carriage 61, the idling rollers 27 and 37 are free rolling and located between the vertical sides of this carriage. The lower carriage 62 itself holds the idling rollers 29 and 39. The latter are themselves free rolling and carried by a pair of pneumatic jacks 63 which are fixed against the interior sides of carriage 62. The layout of these jacks allows compensation, in a independent way, of lack of tension which appears in the conveying belts 23 and 33 when the carriages 61 and 62 are moving. Although the latter relocate simultaneously the two pairs of rollers 27, 37 and 29, 39 of a 10 same length in an opposite direction, the lengthening or the shortening of the higher part of the conveying belt 33, for example, between the rollers 36 and 37 cannot be completely compensated by the shortening, or respectively the lengthening, of its lower part between the rollers 38 and 39. This fact results from the geometrical location of the rollers 36, 37, 38 and 39 which exhibit two 15 unequal angles of opposite edges represented by the rollers 37 and 38. So, the unequal length variations of the conveying belts between these rollers have to be compensated at any time by movement of the roller 29 actuated by one of the pairs of jacks 63. The same applies to the conveying belt 23 and to the rollers 26, 27, 28 and 29.

The carriages 61 and 62 slide between the frame 70, for one side by means.of jaws equipped with balls 64 secured against one of the panels of the 14 carriages and slipping each one along a rail 65 interdependent from the aforesaid frame, and for the other side by means of rollers 66 secured against the other panel of carriages 61, 62 and travelling each one on a running tread 67 secured to frame 70. The driving of the carriages is carried out by the engagement of toothed racks 68, secured against the interior panels of the carriages, in the lower part for the carriage 61 and in the higher part for the carriage 62, with a pair of toothed wheels 69 carried on shaft 71 of an electric motor 72. The speed and accelerations of the carriages 61 and 62 can thus be precisely controlled by virtue of the control flexibility of the electric motor 72. Moreover, one will ensure as well as possible the load balances of these two carriages in order to compensate (he dynamic effects generated when the latter are moving.

In order to create a sharp and precise separation of stream 22, a grip :can close on this stream between the rollers 27 and 37 of respective conveying belts 23, 33. This grip is made of a transverse bar 76 carried at the ends of two Is parallel bent arms 77 which can pivot around a rotation axis 78 crossing the upper carriage 61. To grip the stream 22, the two bent arms 77 are rotated upwards and the transverse bar 76 compresses the stream against a series of support rollers 79 which are disposed in a selected arrangement over the stream 22 between the rollers 27 and 37.

In a situation initially represented in fig. 1, the conveying belts 23 and 33 both have a constant identical speed so that the travelling of stream 22 of the conveying belt 23 towards the conveying belt 33 is not noticeable. When the numrber of sheets required for a pile is to be found on the conveying belt 33, the driving mechanism 60 of the carriages 61 and 62 is actuated and involves progressively the downstream and upstream ends of the respective conveying belts 23 and 33 in the direction of arrow 1 until the speed of movement is identical to the running speed of the conveying belt 23. At this time, the grip closes up on the conveying belt 22, then the speed of the conveying belt 33 fastens quickly and thereby creates the separation of the stream 22 of which the downstream part 32 comes to flow relatively fast into the stacker 40 as illustrated on fig. 3. During this operation, the roller 36 of the downstreamn end of the conveying belt 33 is moved vertically upwards by the elevator 50 so that the drop height of sheets 2 on the top of the forming pile 42 is at any time constant and optimal. Meanwhile, the carriages 61 and 62 have not stopped moving, towards downstream for the carriage 61 and upstream for the carriage 62, at the same speed as the conveying belt 23 while following the continuous progression of the stream 22. In order to make sure that the whole stream 32 left the conveying belt 33 the high flowing speed of this conveying belt is still maintained for a couple of fractions of seconds after the theoretical flowing of the last sheet of stream 32.

Then this speed decelerates until it is identical again to that of the conveying belt 23. At this time the grip 75 opens, releasing the progression of stream 22 onto the conveying belt 33, and the driving of carriages 61 and 62 is gradually slowed 16 down until it is reversed for returning the carriages back to their initial respective position. Just after the theoretical flowing of the last sheet of stream 32 on the pile 42, this pile can be immediately removed by the actuation of the belt 43 which carries it towards one of the outputs of the machine. As soon as possible, but even before the carriages 61, 62 are back into their initial position or before the pile has entirely left the slope 41, the elevator 50 descends again while still actuating the downstream end of the conveying belt 33 which returns to its low position. A new cycle can then start again.

During the stacking phase of sheets 2 of stream 32, the tracks 41 are generally laid out in a horizontal normal position allowing the delivery of these sheets. It should be noted out here that there are as many piles 42 as there are lines 9 of streams on the conveying belt 33 which, simultaneously, are assembled on the belts 43 of parallel tracks 41. However, if a printing defect was scanned for example on the sheets of one or the other of these lines 9, one or the tracks 15 41 intended to this line of defect sheets can be swivelled downwards by one or several pneumatic jacks 44, even before the beginning of the sheets stacking.

Thus, only the stream 32 of the line which contains defective sheets will be directly delivered from the stacker onto a reject evacuation belt 90 placed transversely according to the travel of the streams. This situation is illustrated on fig. 5 where only the downstream part of a device according to this invention is shown.

17 Fig. 6 and 7 show the details of the mechanism which allows at the sarne time the rotating one of the tracks 41 and the driving into rotation of its belt 43.

Fig. 6 is a part sectional profile view of this same track 41 according to the section line VI-NT of fig. 7. The illustration of fig. 6 shows the track 41 in two different positions, one horizontal in full lines, and the other vertical or rotated downwards in dot-dash lines. This track is made of a reversed U-shaped plate as it is better shown on fig. 7. On this plate are secured rollers 46, assembled on rotation free bail bearings, around which the belt 43 is travelling. This belt is permanently secured to a ring 47 positioned and carried on an expansible driving shaft 48 whose diameter can increase, allowing thus to firmly maintain the o: aforementioned ring 47. When the expansible shaft 48 is set into rotation. it actuates also the ring 47 which, by contact, makes the belt 43 turning around. In order to allow simultaneously the downwards swing of the track 41 by the jack 44, a ball bearing 49 is assembled on each side of the ring, 47, on a flange 94, in :15 a groove provided on each panel of tHis ring. One part of this ball bearing 49 is interdependent from the ring 47, whereas the other pan,. attached to the flange 94 of this same ball bearing is interdependent only from the plate 45 which constitutes the frame of the track 41. By means of functioning of this ball bearing and by virtue of its layout as above described, the plate 45 can then be rotated downwards or upwards through the jack 44 in a completely independent way from the rotation of belt 43 and its driving system.

I8 To achieve a good stacking of sheets 2 on the belts 43 of tracks 41, a transverse jogger 80 is provided in the stacker 40 and allows the longitudinal alignment of the sheets of pile 42 against front stops 81. When they leave the conveying belt 33, the sheets are projected in their fall against the aforementioned front stops 81 Each stop is secured against the upstream side of a carriage 82 assembled between two side arms 83 of frame 51. To be able to adjust these front stops according to the format of sheets 2, the carriage 82 is movable in the direction of movement of the strearns by means of a wheel 84. Each stop 81 is movable and also transversely removable so that it can be correctly positioned in front of the pile to which it relates. Moreover, each front stop can be equipped with a template, or a shaped element not shown here, allowing to fit as well as possible the shape of the front edge of sheets 2 to be aligned. In the upstream *.:part of the transverse jogger 80 is one or more back stops 85 actuated by a periodic oscillatory movement into the direction shown by the double arrow 5 on fig. 1. Such an oscillation can be reached for example starting from a eccentric arm 86 related to the axis of an engine 87. This vibratory back and for-th motion allows the continuous arrangement of the sheets 2 when they pile up, by constraining them to pile up correctly against the front stops 81. The back stops can of course also be equipped with shaped templates and can also be transversely moved just like the front stops. To carry out the transversal alignment of the sheets piles a second jogger device, not shown here but intended 19 to act in substantially the same way, is generally used. However, a detail of the first jogger device 80 lies in the fact that it is equipped with a plurality of nozzles 88 which blow air under the sheets 2 during their fall. These air blasts ensure the good piling of piles 42 by preventing the sheets from turning over or from falling under a too stronger attacking angle. The air blasts strength, their amount, their position and the orientation of the nozzles are as many easily adjustable parameters selected according to the size of the delivered sheets and to their basis weight. It should also be mentioned that such jogger devices are removable and easily adaptable to the various works to deal with allowing, when one has at least two pairs of them, preparation of them before out of the machine by fitting them for the next operation.

By means of the device which has now been described above it will be seen that, on one hand, the travelling of elevator 50 depends only on the height of pile 42 and that, on the other hand, without taking into account the real maximum 15 speeds which can be reached by the elevator 50 and by the stripping belt 43. the minimum necessary waiting time before being able to remove the elevator in its initial position depends only on the height and on the longitudinal dimension of this same pile 42. Thus, the moving back into its low position of the elevator and of the end of the conveying belt 33 can advantageously be carried out as soon as the upstream side of pile 42 has been travelling under the front stop 81 of jogger 80, thus even before this pile has left the track 51 on which it was secured.

Many improvements can be brought to the device of this invention within the framework of the claims.

Claims (9)

1. A flat element delivery and ejection device for a machine which processes such elements, in particular a production machine for continuous processing which delivers a plurality of lines of flat elements shingled into parallel streams on a first conveyor belt, moves the stream to said delivery and ejection device onto a second conveyor belt which extends around a plurality of rollers or idling rollers, said second conveyor belt is arranged to operate at a 10 constant moving speed which is lower than that of the first conveyor belt so as to allow formation of new stream, more compact than the initial ones, said streams then being conveyed by a third conveyor belt, extending around a plurality of rollers or idling rollers and extending in a manner similar to the 999 other conveyor belts across the whole effective width of said delivery and 15 ejection device, said machine processing parts of streams which are recurrently delivered at higher speed into a stacker by a driving and shingle interrupting mechanism which in effect lengthens the useful surface of the second conveyor belt defined by the upper rollers and simultaneously shortens by the same amount the useful surface of the third conveyor belt, defined by the upper rollers characterised in that the stacker is arranged so as to separately reject at least one stream towards a reject conveyor belt collecting flat elements which

2.2 elements have been identified as being defective, the shingle interruption mechanism comprise two carriages, an upper carriage and a lower carriage, which can move simultaneously, at the same speed and in opposite directions along an axis parallel to the lines of streams. 2. A device according to claim I, characterised in the fact that the upper and lower carriages are of equivalent mass and driven by an electric motor which way of a pair of toothed wheels and a pair of toothed racks each one interdependent of one of the two carriages, and in fact in that each carriage 10 comprises only one roller of each conveyor belt.

3. A device according to claim 2, characterised in the fact that the rollers of the lower carriage, are each arranged so that they can be independently moved one from the other into the direction of movement of the carriages.

4. A device according to claim 1, characterised in that the stacker includes a plurality of adjustable tracks which can provide: parts of horizontal surfaces on which can be formed piles of flat elements; conveying surfaces comprising endless belts which when set into operations allow the movement of said piles towards an output; 23 opening shutters which can separately be swung downwards to reject flat elements towards the reject conveyor.

A device according to claim 1, characterised in that the stacker includes, a movable jogger for arranging for flat elements into piles, said jogger device having in its downstream part shaped front stops which are removable and adjustable longitudinally by movement of a carriage, and movable transversely relative to the direction of displacement of the upper and lower carriages and provided in its upstream part with shaped back stops which are removable and 10 transversely adjustable.

6. A device according to claim 5, characterised in that the moveable jogger device and the roller, which comprise the downstream end of the final "conveyor belt, are both interdependent and vertically removable, upwards while 15 following the height progression of piles which are formed on the tracks, and S"downwards during the moving of the piles on the tracks.

7. A device according to claim 5, characterised in that the jogger includes nozzles which can blow air in the direction of the front stop at a height located below the tilting plan defined by the upper rollers of the third conveyor belt. 24

8. A device according to claim 5, characterised in that the strength of the air flow their amount, their position and the orientation of the nozzles are adjustable parameters, selected according to the size of the flat elements and their weight.

9. A device according to claim 4, characterised in that each track includes an armature, supporting rollers around which extends the endless belt, which is 3 *interdependent of a ring of at least one mechanical bearing, the other ring of the said mechanical bearing being interdependent only of another ring which, 1. 0 on one hand is in contact with the endless belt, and on the other hand can be firmly maintained on a driving shaft to permit the setting into rotation of said endless belt. Dated this thirteenth day of December 2001 Bobst S A SPatent Attorneys for the Applicant: F B RICE CO